complete: add page (#2136)

pages/common/complete.md

@@ -0,0 +1,15 @@
+# complete
+
+> Provides argument autocompletion to shell commands.
+
+- Apply a function that performs autocompletion to a command:
+
+`complete -F {{function}} {{command}}`
+
+- Apply a command that performs autocompletion to another command:
+
+`complete -C {{autocomplete_command}} {{command}}`
+
+- Apply autocompletion without appending a space to the completed word:
+
+`complete -o nospace -F {{function}} {{command}}`